Qualitative and quantitative interpretations of aeromagnetic anomalies over Ogoja and Bansara areas of Anambra Basin, Lower Benue Trough of Nigeria were carried out using spectral analysis and source parameter imaging methods. The study area which covers an area of approximately 6050 km2 lies within latitude 60° 0' to 7° 0' North and longitude 8° 30' to 9° 0' East. The regional anomaly was separated from the total magnetic intensity map to obtain the residual anomaly using first order polynomial fitting technique. The residual data was analyzed spectrally to obtain 18 spectral blocks for sedimentary depth estimates (deep and shallow depths). The edges and causative bodies of the residual anomaly were also sharpened to reduce anomaly complexity as well as fault trend amplification using first, second and horizontal derivatives. The 3-D basement topography map of the study area shows linear depression with deepest sedimentary thickness at the southeastern region of the study area, which implies that the feasibility of hydrocarbon potential will be higher in Bansara area than in Ogoja. The deepest depths obtained from spectral analysis and source parameter imaging are 5437.0 and 5059.9 m, respectively. 

 

Key words:  Spectral analysis, source parameter imaging, magnetic anomaly, sedimentary thickness, intrusive bodies, hydrocarbon potentials.